Multiple foam energy absorbing substrate assembly

ABSTRACT

The present invention relates to a multiple foam substrate of predetermined shape and a method of manufacturing the substrate. The substrate is a multiple foam substrate which may be manufactured by the method with a mold having first and second mold cavities. The method includes injecting a first foam into the first mold cavity sufficiently to fill the first mold cavity and storing the first foam in the first mold cavity for a predetermined time sufficient to form a substantially non-mixing surface on the first foam. The method further includes injecting a second foam into the second mold cavity and onto the non-mixing surface on the first foam sufficiently to fill the second mold cavity. The method further includes storing the second foam in the second mold cavity for a predetermined time sufficient to bond the first foam to the second foam along the non-mixing surface.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a division of U.S. application Ser. No. 09/561,002filed Apr. 28, 2000 now U.S. Pat. No. 6,451,233.

TECHNICAL FIELD

The present invention relates to a multiple foam substrate for impactenergy absorption and airbag deployment.

BACKGROUND ART

There is a growing need to improve the impact energy absorptionproperties of automotive interior trim substrates. Such sheet metalstructures include pillars, side rails, and roof structures. However,the industry has been challenged in determining a cost effective way ofmanufacturing interior trim substrates and interior components in orderto meet industry demands. For example, manufacturers continue to searchfor ways of improving the properties of substrates for absorbing energyin a cost saving manner while providing structural support.

One challenge that manufacturers are faced with is that impact energyabsorption throughout the passenger compartment, such as on pillars,side rails, or the roof structure of a vehicle, requires differentenergy absorption material, including molded foam or beads. This is dueto the vehicle structure design which typically includes a plurality ofsheet metal pieces that form the passenger compartment of a vehicle. Thethickness and geometric stiffness of the sheet metal typically determinethe amount of energy absorption material required. That is, the thickerand/or stiffer the sheet metals is, the more absorption material isrequired to meet industry demands. Thus, different energy absorptionmaterials would be useful to have in interior trim substrates.

There is also a growing need to improve airbag deployment properties ofautomotive interior trim substrates. Upon impact, airbags may bedeployed from various locations within a vehicle compartment, such aspillars, side panels, roof structures, and front panels. However, theindustry has also been challenged in determining a cost effective way ofmanufacturing interior trim substrates with airbags and interiorcomponents in order to meet industry demands. For example, manufacturerscontinue to search for ways of improving the properties of a substratefor accommodating an airbag disposed to be deployed from the substrate.

A deployable airbag is typically disposed between the metal sheetstructure, such as a pillar, and the interior trim substrate. The airbagis typically fastened to an area of the sheet metal structure andadjacent the energy absorbing part which is covered by an interiorsubstrate. This separate manufacturing and assembly process used indisposing the deployable airbag between the structure and the interiortrim substrate results in additional manufacturing time and costs.

Although current energy absorbing parts are adequate, improvements canbe made thereupon. Currently, multi-component parts are manufactured forimpact energy absorption and air bag deployment purposes. Somemulti-component parts are separately manufactured and then combined tocomprise a part which is fastened to an area of a vehicle compartment,such as a pillar. More particularly, a single foam is molded to form ashape of a vehicle component to which it may be attached. The moldedfoam is then adhered to a predetermined area on an interior trimmaterial or a shell which then fastens onto the structure of a vehicle.The separate manufacturing processes used in forming the molded foam andthe interior trim substrates result in additional manufacturing time andcosts.

Thus, what is needed is an improved system and method of making anintegrally formed substrate that more efficiently meets the industrydemands for energy absorption on collision impacts.

What is also needed is an improved system and method of making asubstrate that provides for a deployable airbag system for deploymenttherefrom.

DISCLOSURE OF INVENTION

An object of the present invention is to provide for a method ofmanufacturing a multiple foam substrate of a predetermined shape forselective impact energy absorption with a mold having first and secondmold cavities. The method includes injecting a first foam into the firstmold cavity sufficiently to fill the first mold cavity, and storing thefirst foam in the first mold cavity for a predetermined time sufficientto form a substantially non-mixing surface on the first foam. The methodfurther includes injecting a second foam into the second mold cavity andonto the non-mixing surface on the first foam sufficiently to fill thesecond mold cavity, and storing the second foam in the second moldcavity for a predetermined time sufficient to bond the first foam to thesecond foam along the non-mixing surface, whereby to define the multiplefoam substrate having the predetermined shape.

Another object of the present invention is to provide for a method ofmanufacturing a multiple foam substrate of a predetermined shape forselective impact energy absorption and airbag deployment with a moldhaving first and second cavities. The method includes injecting a firstfoam into the first mold cavity sufficiently to fill the first moldcavity, and storing the first foam in the first mold cavity for apredetermined time sufficient to form a substantially non-mixing surfaceon the first foam. The method further includes loading a deployableairbag onto the non-mixing surface. The method further includesinjecting a second foam into the second mold cavity and onto thenon-mixing surface adjacent the deployable airbag sufficiently to fillthe second mold cavity, and storing the second foam in the second moldcavity for a predetermined time sufficient to bond the first foam to thesecond foam along the non-mixing surface, whereby to define the multiplefoam substrate having the predetermined shape.

Yet another object of the present invention provides for a multiple foamsubstrate of a predetermined shape for impact energy absorptionmanufactured by the process of injecting a first foam into a first moldcavity of a mold sufficiently to fill the first mold cavity, storing thefirst foam in the first mold cavity for a predetermined time sufficientto form a substantially non-mixing surface on the first foam, injectinga second foam into a second mold cavity of the mold and onto thenon-mixing surface on the first foam sufficiently to fill the secondmold cavity, and storing the second foam in the second mold cavity for apredetermined time sufficient to bond the first foam to the second foamalong the non-mixing surface.

Yet another object of the present invention is to provide for a mold formanufacturing a multiple foam substrate of predetermined shape. The moldcomprises an upper portion and a lower portion. The upper portion has afirst surface from which a first section extends and a second surfacefrom which a second section extends. The second surface is adjacent thefirst surface. The lower portion has a lower surface from which a lowersection extends. The first section is configured to engage with thelower section to define a first mold cavity at a first closed position.The second section is configured to engage with the lower section todefine a second mold cavity at a second position.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a perspective view of a mold drawn that may be used incarrying out the present invention;

FIG. 2 is a cross-sectional view of the mold of FIG. 1 to depict a firstfoam injected in a first mold cavity of the mold;

FIG. 3 is a cross-sectional view of the mold to depict a second foaminjected into a second mold cavity of the mold;

FIG. 4 is a flow chart of one method implemented in making a multiplefoam substrate with the mold of FIG. 1 in accordance with the presentinvention;

FIG. 5 is a cross-sectional view of a multifoam substrate made by themethod of FIG. 4;

FIG. 6 is a cross-sectional view of another multiple foam substrateformed with an airbag made by the method of FIG. 4; and

FIG. 7 is a cross-sectional view of yet another multiple foam substrateformed with a fastener by the method of FIG. 4.

BEST MODE FOR CARRYING OUT THE INVENTION

FIG. 1 illustrates a mold 10 that may be used for manufacturing amultiple foam interior trim substrate in accordance with one embodimentof the present invention. As shown, mold 10 includes lower portion 12and upper portion 14.

FIG. 2 illustrates a cross-sectional side view of mold 10 in a firstopen position. As shown, upper portion 14 includes first surface 16 fromwhich first section 20 extends downwardly toward lower portion 12. Upperportion 14 further includes second surface 18 from which second section22 extends. Second section 22 includes extension 24 integrally extendingfrom second section 22. Lower portion 12 includes lower surface 26 fromwhich lower section 28 extends upwardly. From the open position, firstsection 20 is lowered to a first closed position and engages lowersection 28 to define first mold cavity 32. Moreover, upper portion 14includes first injection hole 36 formed thereon through first surface 16and first section 20. Hole 36 is in fluid communication with first moldcavity at the first closed position. First injection hole 36 is formedto receive first nozzle 42 through which first foam 43 is injected intofirst mold cavity 32.

FIG. 3 illustrates a cross-sectional side view of mold 10 in a secondopen position. From the second open position, second section 22 islowered to a second closed position and engages lower section 28 todefine second mold cavity 34. Upper portion 14 further includes secondinjection hole 38 formed thereon through second surface 18 and secondsection 22. Hole 38 is in fluid communication with second mold cavity 34in the second closed position, as shown in FIG. 3. Second injection hole38 is formed to receive second nozzle 44 through which second foam 45 isinjected into second mold cavity 34, as shown in FIG. 3. As shown, upperportion 14 rotates approximately 90° such that second surface 18 facesdownwardly toward lower surface 26 in order for second section 22 toengage with lower section 28.

Mold 10 may include conventional controls, plumbing, and mold-actuatingmechanisms to allow proper operation of lower portion 12 and upperportion 14. For example, portions 12, 14 of mold 10 may be mounted ontie-rods. In this embodiment lower portion 12 is stationary, while upperportion 14 is movable to permit opening and closing of portions 12 and14. Moreover, upper portion 14 is configured to rotate providing pivotalmovement such that second section 22 faces downwardly and may engagewith lower section 28. Actuations of portions 12,14 may be by hydraulic,air cylinder, or manual.

Preferably, first and second foams 43,45 are polyurethane foams havingdifferent properties. For example, first foam 43 is preferably a highdensity flexible urethane foam and second foam 45 is preferably a rigidstructural foam. High density urethane foam is defined as foam having adensity of a range between 80-125 kg/m³. Structural foam is defined asurethane foam having a density of a range between 40-150 kg/m³. Thefoams may respectively be supplied through their respective nozzles fromseparate conventional mixheads (not shown) which dispense a mixture ofpreferably isocyanate and polyol systems into the mold in the closedpositions. Moreover, the isocyanate and polyol systems may be stored inseparate tanks, and metered to the respective mixhead. It is to be notedthat other foams may be used which would not fall beyond the scope orspirit of the present invention. It is to be noted that the materialcomprising the foam, e.g., polyurethane, may be recycled material orvirgin (non-recycled) material.

FIG. 4 illustrates one method 110 implemented to manufacture a multiplefoam interior trim substrate with mold 10 of FIGS. 1-3. As shown in box112, the method includes providing first foam 43 and second foam 45 ofdiffering physical properties. In this embodiment, first foam 43 is aflexible polyurethane foam and second foam 45 is a rigid polyurethanefoam. A difference in the densities between foams 43, 45 provides adifference in physical properties of the two foams. In this embodiment,first foam 43 has a density less than the density of second foam 45.However, first foam 43 may have a greater density than second foam 45.In such embodiment, mold 10 of FIGS. 1-3 will have sections configuredto form interior trim substrate 210.

In this embodiment, first foam 43 is injected into first mold cavity 32,as shown in box 114 of FIG. 4. First foam 43 is injected into first moldcavity 32 through hole 36 by first nozzle 42 at a temperature betweenabout 70° and 90° F. and at a high pressure of up to 3000 pounds persquare inch gauge (psig). Within about 1-15 seconds, first mold cavity32 is filled with first foam 43, and nozzle 42 is closed. First foam 43in first mold cavity 32 is stored for 2-3 minutes in order to cure toform a substantially non-mixing surface of a resulting part as shown inbox 116. During the curing duration, the resulting part increases instrength and stiffness enough to substantially prevent mixing of fistand second foams 43, 45 when second foam 45 is injected thereon, asdescribed below.

After storing first foam 43 in first mold cavity 32, upper portion 14 ofmold 10 disengages from stationary lower portion 12 by moving upwardly.Upper portion 14 then rotates about 90° in order for second surface 18to face downwardly toward lower section 28 of lower surface 26. Upperportion 14 then moves downwardly to engage second section 22 with lowersection 28. Through hole 38, second nozzle 44 injects second foam 45into second mold cavity 34 onto the non-mixing surface of first foam 43,as shown in box 118. When second mold cavity is filled, within about1-15 seconds, nozzle 44 closes at a temperature between about 70° and90° F. and at a high pressure of up to 3000 pounds per square inch gauge(psig). As shown in box 120, second foam 45 is stored in second moldcavity 34 for 2-3 minutes in order to cure and bond with the non-mixingsurface of first foam 43 to define the multiple foam substrate havingthe predetermined shape. The curing duration allows the substrate tobuild up enough strength and stiffness to be bonded with the non-mixingsurface of the resulting part and to be removed from the mold whensufficient curing is complete. After removal of the substrate, thesubstrate is post-cured for 1-2 days at approximately 70° F. to enhancephysical properties and part stability.

As shown in FIG. 5, interior trim substrate 210 includes high densityurethane foam portion 212 and structural foam portion 214 integraltherewith to define inner surface 216 and outer surface 218. In thisembodiment, high density urethane foam portion 212 may act as a softaesthetic outer layer for a show surface of an A-pillar section of avehicle compartment. Structural foam portion 214 acts as an energyabsorbing layer for collision impacts.

Outer surface 218 acts as a decorative cover or self-skinning surfacehaving aesthetic features, eliminating the need of cloth disposedthereon. This may be accomplished by having portions 12, 14 of mold 10be in communication with one or a plurality of heating platens (notshown) in order to heat mold 10 during method 110 of the presentinvention. The heating platens may be heated to a temperature rangingbetween 120° F. and 200° F. in order to heat mold 10 to a temperaturebetween 120° F. and 150° F. When the mold 10 is heated, the foam incontact with lower section 28 is molded to the shape of either firstmold cavity 32 or second mold cavity 34. The molded foam takes on agrain texture and firm surface. As a result of heating mold 10, interiortrim substrate 210 has outer surface 218 with aesthetic features that donot require cloth or an outer layer to be placed thereon. If desired,additional cloth or outer layer may be attached thereto in order toprovide a more aesthetic look.

Alternatively, the decorative cover or outer layer may be placed in mold10 prior to injecting foam in mold 10, eliminating the need of attachingan outer layer after heating. In this embodiment, the decorative covermay be applied by a cloth placed thereon, as mentioned above, or by acolor spray sprayed onto mold 10 prior to injecting foam in mold 10.Other ways of applying a decorative cover in the mold prior to injectingfoam in the mold do not fall beyond the scope and spirit of thisinvention. Also, although FIG. 5 depicts inner surface 216 flankingsheet metal structure 220, it is to be noted that surface 216 may beconfigured adjacent only one side of structure 220, as desired.

As shown in FIG. 6, substrate 310 includes high density urethane foam312, structural foam 314 attached to foam 312, and deployable airbag 316also attached to foam 312. This may be accomplished by loadingdeployable airbag 316 onto high density urethane foam 312 after storingfirst foam 43 in first mold cavity 32 and prior to injecting second foam45 in second mold cavity 34. In this embodiment, second section 22 is beformed without extension 24 to allow space for airbag 316 on foam 312.It is to be noted that airbag 316 may be loaded onto foam 312automatically, e.g., by robotics, or manually, e.g., by hand. As shown,high density urethane foam 312 also includes notch 318 formed betweenairbag 316 and structural foam 314 in order to accommodate deployment ofairbag 316. As airbag 316 deploys upon impact, notch 318 provides aportion of high density urethane foam 312 adjacent airbag 316 to flexaway from sheet metal structure 320, allowing airbag 316 to deploy inthe vehicle compartment.

As shown in FIG. 7, conventional fastener 413 or a plurality offasteners 413 may be disposed within the mold in order to be bonded tofoams 412, 414 to provide an interior trim substrate 410 having anintegral fastener that may be directly attached to structure 420 of thevehicle. This eliminates the need of adhesives used to glue thefasteners onto the substrate.

While embodiments of the invention have been illustrated and described,it is not intended that these embodiments illustrate and describe allpossible forms of the invention. Rather, the words used in thespecification are words of description rather than limitation, and it isunderstood that various changes may be made without departing from thespirit and scope of the invention.

What is claimed is:
 1. A multiple foam substrate of a predeterminedshape for impact energy absorption manufactured by the process ofinjecting a first foam into a first mold cavity of a mold sufficientlyto fill the first mold cavity, storing the first foam in the first moldcavity for a predetermined time sufficient to form a substantiallynon-mixing surface on the first foam, loading an airbag into the moldcavity, injecting a second foam into a second mold cavity of the moldand onto the non-mixing surface on the first foam to fill the secondmold cavity except for a notch formed between the second foam and theairbag to aid in deployment of the airbag, and storing the second foamin the second mold cavity for a predetermined time sufficient to bondthe first foam to the second foam along the non-mixing surface.
 2. Anenergy absorbing substrate assembly manufactured by the process,comprising: injecting a first foam into a first portion of a moldcavity; storing the first foam in the first mold cavity until anon-mixing surface is formed on the first foam; loading a deployableairbag into the mold cavity after the non-mixing surface is formed onthe first foam in the first portion of the mold cavity and beforeinjecting the second foam into the second portion of the mold cavity;injecting a second foam into a second portion of the mold cavity andonto the non-mixing surface of the first foam and forming a notchbetween the airbag and the second foam to aid in deployment of theairbag; and storing the second foam in the second portion of the moldcavity until the second foam is adhered to the first foam.
 3. The energyabsorbing substrate assembly of claim 2, further comprising: insertingat least one fastener in the mold to be bonded to either or both of thefoams to provide an integral fastener for the substrate assembly.